The present invention generally relates to sidewall panel systems for aircraft cabins and, more particularly, to a sidewall panel having reconfigurable inserts allowing the panel to be placed anywhere along the cabin wall.
Present-day commercial aircraft cabins typically have various layouts depending upon the use to which the aircraft is being put. These layouts are made up of such items as seating for personnel, overhead bins for storage of personal items, sidewall panels covering the interior walls of the cabin, and monuments (i.e., closets, restrooms, interior dividers, and other space-defining items). The sidewall panels may have panel openings that oppose structural windows in the outer wall of the fuselage, so that passengers can see out of the aircraft. When there is a structural window in the outboard wall of the aircraft, a sidewall panel opening is aligned with the structural window and an inner window assembly is inserted through the sidewall panel to mate with the structural window. The sidewall panels must be configured to match different layouts with structural windows having different spacing arrangements. Aircraft designers desire consequently to minimize the number of different types of sidewall panels with respect to the panel openings required to accommodate these various layouts and structural window arrangements.
Therefore, efforts have been made to standardize the configuration of the sidewall panels so as to reduce panel inventory and tooling costs. Typically, a sidewall panel may have a given width when accommodating a single opening and a double width when accommodating two openings. For single width panels, there may be two more types, one with an opening and one without an opening. For double width panels, there may be four types, i.e. an opening on the left, an opening on the right, openings on both sides, and no openings. This is necessary since monument placement within the layout generally requires a standardized profile along the sidewall panel so that the monument may conform to the panel as needed. As can be readily seen, as the number of sidewall panel types that have sufficient width to accommodate three or more openings increases, the number of panel/window opening permutations increases geometrically. This in turn increases the different distinguishable sidewall panel types that must be fabricated. Each separate panel type requires different tooling, which in turn increases expense. Furthermore, in certain places in the airplane, non-standard frame spacings may require different width sidewalls, which further multiplies the number of different sidewall configurations and external window arrangements.
When an aircraft operator reconfigures the cabin interior, e.g. adding or reducing seats in different seating classes, the monuments for that layout may also have to be moved, which may result in covering or uncovering window openings. This may require different sidewall types to be installed. Therefore, the aircraft owner must also stock multiple spare sidewall configurations to cover each of the sidewall variants.
Sculpturing around the window opening complicates the reconfiguration process. On some aircraft models, the sidewall profile is different along its length due to sculpturing around the windows, and therefore simply blanking out a window hole would still result in a unique interface between the monument and the sidewall to fill the gap between the outboard monument profile and the inboard sidewall profile.
More specifically, prior art sidewall panels must have multiple configurations and types, so that different cabin layouts and window arrangements may be accommodated. Prior art sidewall panels also provide sculpturing of the sidewall panel adjacent to the panel opening to provide more room for passengers. Such sidewall panels typically span a space between three frames, or ribs, of a fuselage primary structure with an external structural window interposed between each frame, and thus are said to cover two frame bays. Additionally, some single frame bay sidewalls may also be used to interface with monuments and doorways or when there is an odd number of frame bays between the ends of the sidewall. Multiple sidewall configurations are thus required in the prior art to support monument locations. Typical configurations required are as follows:    Two frame bay panel, left and right sides with window openings    Two frame bay panel, left with window opening and right without window opening    Two frame bay panel, left without window opening and right with window opening    Two frame bay panel, no window openings    One frame bay panel with window    One frame bay panel without windowThus, six separate and distinct sidewall types must be constructed and stocked in order to support different cabin layouts, according to the prior art.
FIGS. 1A and 1B illustrate a typical situation that is frequently encountered when reconfiguring aircraft cabins. Referring to FIG. 1A, three sidewall panels 120a, 120b, 120c are shown, each sidewall panel being of a different type. A closet monument 140 is shown between the first seat row 110a and the second seat row 110b. Since the closet monument 140 overlaps sidewall panels 120a and 120b, then sidewall panel 120a is of a type having a left side with a window opening and a right side without a window opening, and sidewall panel 120b is of a type having a left side without a window opening and a right side with a window opening; sidewall panel 120c is of a type having openings on both sides. Because of window sculpturing, the prior art solution for this particular configuration change has been to provide these three panel types. If it is desired to move the closet monument 140 from a location indicated in FIG. 1A to a location indicated in FIG. 1B, then seat rows 110b and 110c must be moved forward and the closet monument 140 must be moved aft; in order to cover window openings 130b and 130c, all three sidewall panels 120a, 120b, and 120c, must be removed and relocated to a different position along the sidewall; this would require the additional removal of seat rows 110a and 110d in order to access all the sidewall panels 120a–120c. 
A typical sidewall panel 200 is shown according to the prior art. According to FIG. 2A, a vertical cross-sectional view of the sidewall panel 200 may be seen. The sidewall panel 200 may have a panel opening 210 into which is inserted a window assembly 240. The sculpturing area 230 immediately around the panel opening 210 may be curved in an outboard direction, indicated by the arrow labeled 288. This outboard curvature may provide additional room to a passenger seated adjacent to the sidewall panel 200, as indicated by the direction of the arrow labeled 299. A flange 250 along around the perimeter of the window assembly 240 may abut the inboard surface 202 of the sidewall panel 200 to hold the window reveal 240 in place within the panel opening 210. As can be readily seen, the replacement of the window assembly 240 by a cover plate to fill the panel opening will not affect the sculpturing around the panel opening. Furthermore, the gradual slope of the sculpturing area 230 as it conforms to the inboard surface 202 may be so gradual so that it is difficult to provide an adequate locking mechanism for a cover or to provide a cover having sufficient thickness around its perimeter to smoothly blend to the inboard surface 202.
The prior art contains a number of examples of how the sidewall panel configuration has been addressed. U.S. Pat. No. 6,082,674 discloses a sidewall panel in which the sculpturing around the inner window is contained in the sidewall so that the inner window, comprising a dust cover and window shade, may be affixed to the outboard side of the sidewall panel. There is no suggestion of using a window reveal to interface the inner window assembly to the sidewall panel, and presumably the opening perimeter of the sidewall panel functions as a window reveal. European Pat. App. No. EP 1306302 A2 discloses a sidewall panel having a snap-in window assembly, in which the sculpturing around the panel opening is shown to be a portion of the sidewall panel. An inner window assembly includes a window reveal that attaches to the opening using snap-in fasteners.
As can be seen, there is a need for reducing the number of sidewall panel configurations by providing modular and interchangeable components to the sidewall system so that the numbers of different types of sidewall panels may be reduced and standardized.